"Things will be cooler on Tuesday morning as a front moves up from the South Island," said Lee.
"The rain is likely to clear and the strong southeasterly winds are likely to ease up later in the morning."
The temperature on Tuesday is expected to reach a high of 15C with an overnight low of 5C.
Wednesday is expected to be partly cloudy, with rain developing and light northeasterly winds. The temperature is once again expected to reach a high of 15C and dip to 5C overnight.
Rain is forecast for Thursday the temperature is expected to reach a high of 15C again although a northwesterly change is expected to bring a milder overnight low of 8C.
The rainfall is expected to be lighter than last week when 15.8mm was recorded at Whanganui Airport on Monday, July 19 and 10.2mm on Thursday, July 22.